Session: Physical Chemistry Poster:

Poorly passivated nanocrystal (NC)-ligand interfaces result in poor quantum yields and short excited state lifetimes, both which inhibit photocatalytic performance in NCs. This green synthesis produced ZnSe Mn doped NCs with optimal optical qualities including high quantum yields (QYs) in aqueous solution (56%), distinct absorption band gaps, long excited state lifetimes, and monodispersity in size and shape. Through ligand exchange from native stearate ligands to 3-mercaptopropionic acid (MPA) ligands, the quantum yields of ZnSe Mn doped NPs have been increased from 26% to 56% and their excited state lifetimes have been extended from 100 µs to 300 µs. Using time resolved photoluminescence (TRPL) spectroscopy and transient absorption (TA) spectroscopy we have shown that the ZnSe Mn doped NC is capable of transferring electrons over the entire length of its long lived excitonic lifetime (∼300 μs). This NC is able to participate in collisionally gated charge transfer with a diffusing molecule, a property that potentially enhances the yield of photocurrent generation in a photoelectrochemical cell.

John Asbury

Pennsylvania State University

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